PageRange.cpp

/*
    Scan Tailor - Interactive post-processing tool for scanned pages.
    Copyright (C)  Joseph Artsimovich <joseph.artsimovich@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "PageRange.h"
#include <boost/foreach.hpp>

std::set<PageId>
PageRange::selectEveryOther(PageId const& base) const
{
	std::set<PageId> selection;
	
	std::vector<PageId>::const_iterator it(pages.begin());
	std::vector<PageId>::const_iterator const end(pages.end());
	for (; it != end && *it != base; ++it) {
		// Continue until we have a match.
	}
	if (it == end) {
		return selection;
	}

	int const base_idx = it - pages.begin();
	int idx = 0;
	BOOST_FOREACH(PageId const& page_id, pages) {
		if (((idx - base_idx) & 1) == 0) {
			selection.insert(page_id);
		}
		++idx;
	}

	return selection;
}